gamma-Glutamyltransferase bound to prostatic subcellular organelles and in free form in human seminal plasma.

Most of the gamma-glutamyltransferase occurring in semen was found to be bound to the membranes of prostatic organelles, as is the case with Mg++-Ca++-dependent ATPase, and Zn++-dependent peptidase hydrolysing succinyl (alanine)3-paranitroanilide. Organelle-bound gamma-glutamyltransferase was released in a water-soluble form by papain. Charge shift electrophoresis revealed the presence in seminal fluid of a small additional amount of gamma-glutamyltransferase that is unbound and water-soluble, but also of prostatic origin. After papain treatment there was no sign of the organelle-bound Zn++-dependent peptidase activity, nor of the Mg++-Ca++ dependent ATPase activity, both having been inactivated by the papain. Both organelle-bound gamma-glutamyltransferase and Zn++-dependent peptidase could be rendered soluble in active form with the non-ionic detergent Triton X-100.